This obviously isn't something new that shows up overnight. We already had dating sims and the likes. But with generative AIs, the catch is that of scale and of personalization: not only it is easier to make thousands of virtual partners at a time, each individual virtual partners can be personalized to our liking.
Not even Huxley could have predicted this lol.
Why would anyone want that? Do you also fantasize about making black mirror a reality